Hollow particle beam emitter

ABSTRACT

A particle beam emitter has a hollow particle beam tube having a first end portion, a second end portion, and a longitudinal axis. An electromagnetic system that includes a voltage supply is electrically coupled to the hollow particle beam tube and is configured to generate a primary electrical current flowing axially in the hollow particle beam tube from the first end portion towards the second end portion. A primary magnetic field associated with the primary electrical current is operable to induce a secondary electrical current in a plasma located within the hollow particle beam tube, the secondary electrical current flowing generally axially within the plasma and causing the plasma to contract inwardly towards the longitudinal axis.

This application claims the benefit of U.S. Provisional Application No.61/495,481, filed Jun. 10, 2011, and is a continuation of U.S.application Ser. No. 13/402,111, filed Feb. 22, 2012, the entirecontents of which are hereby incorporated by reference.

FIELD

Embodiments of the present invention relate to particle beam emittersand, more particularly, to particle beam emitters that include anelectromagnetic system for generating an electromagnetic field toprovide radial confinement of plasma within a hollow particle beam tube.

INTRODUCTION

Fusion power may generally refer to the power generated by nuclearfusion reactions. In one kind of fusion reaction that naturally occursin many stars, such as the sun, two light atomic nuclei fuse together toform a heavier nucleus and, in doing so, release a large amount ofenergy. In some contexts, fusion power may also refer to the productionof net usable power from a fusion source, similar to the usage of theterm “hydroelectric power” to describe the production of net usablepower from water driven turbines. Most design studies for fusion powerplants are based on the controlled creation of fusion reactions togenerate steam used to drive one or more turbine generators.

To date, peak fusion powers of 16.1 megawatts (21,600 hp) withefficiencies of 65% of input power have been achieved. Fusion power ofover 10 MW (13,000 hp) has also been sustained for over 0.5 sec. Presentdesigns are targeting sustained fusion power output of as much as tentimes power input power. For example, 50 MW of input energy is targetedto produce 500 MW of output energy sustained over many minutes. Itshould be understood that these numbers are illustrative only.

SUMMARY

In accordance with one aspect, there is provided a particle beam emittercomprising: a hollow particle beam tube having a first end portion, asecond end portion, and a longitudinal axis; and an electromagneticsystem comprising a voltage supply electrically coupled to the hollowparticle beam tube and configured to generate a primary electricalcurrent flowing axially in the hollow particle beam tube from the firstend portion towards the second end portion, whereby a primary magneticfield associated with the primary electrical current is operable toinduce a secondary electrical current in a plasma located within thehollow particle beam tube, the secondary electrical current flowinggenerally axially within the plasma and causing the plasma to contractinwardly towards the longitudinal axis.

In some embodiments, the particle beam emitter further comprises aplurality of electromagnetic coils aligned axially with and surroundingat least a portion of the hollow particle beam tube for generating anaxial magnetic field within the hollow particle beam tube.

In some embodiments, the particle beam emitter further comprises aninsulation member positioned between the plurality of electromagneticcoils and the hollow particle beam tube.

In some embodiments, the particle beam emitter further comprises a pairof electromagnets positioned exterior to the hollow particle beam tubeand rotatable about the longitudinal axis.

In some embodiments, the voltage supply is configured to generate theprimary electrical current by creating a potential difference betweenthe first end portion and the second end portion.

In some embodiments, the first end portion is configured to receiveplasma from a fuel injector.

In some embodiments, the particle beam emitter further comprises apressure valve positioned between the fuel injector and the first endportion of the hollow particle beam tube.

In some embodiments, the hollow particle beam tube is made from at leastone of tungsten and graphite.

In some embodiments, the hollow particle beam tube comprises a hollowgraphene cylinder having an inner surface coated with tantalum hafniumcarbide.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of various embodiments is provided herein belowwith reference to the following drawings, by way of example only, and inwhich:

FIG. 1 is a schematic view of a thermonuclear reaction system;

FIG. 2 is a schematic view of an exemplary particle beam emitter;

FIG. 3 is a schematic view of a thermonuclear reaction system integratedwith an existing nuclear reactor design.

It will be understood that reference to the drawings is made forillustration purposes only, and is not intended to limit the scope ofthe embodiments described herein below in any way. For simplicity andclarity of illustration, elements shown in the figures have notnecessarily been drawn to scale. The dimensions of some of the elementsmay be exaggerated relative to other elements for clarity. Further,where considered appropriate, reference numerals may be repeated amongthe figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF EMBODIMENTS

It will be appreciated that numerous specific details are set forth inorder to provide a thorough understanding of the exemplary embodimentsdescribed herein. However, it will be understood by those of ordinaryskill in the art that the embodiments described herein may be practicedwithout these specific details. In other instances, well-known methods,procedures and components have not been described in detail so as not toobscure the embodiments described herein. Furthermore, this descriptionis not to be considered as limiting the scope of the embodimentsdescribed herein in any way, but rather as merely describingimplementation of the various embodiments described herein.

Fusion Reaction Rate

As presently understood, fusion reactions are achieved by bringing twoor more nuclei close enough to one another that their residual strongforce (i.e., nuclear force) will act to pull the two or more nucleitogether and form one larger nucleus. When two “light” nuclei fuse, theusual result is the formation of a single nucleus having a slightlysmaller mass than the sum of the masses of the original two nuclei. Inthis case, the difference in mass between the single fused nucleus andthe original two nuclei is released as energy according to thewell-known mass-energy equivalence formula,E=mc ².  (1)However, if two “heavy” nuclei of sufficient mass fuse together, themass of the resulting single nucleus may be greater than the sum of thereactants' original masses. In this case, according to equation (1), anet input of energy from an external source will be required to drivesuch fusion reasons. Generally speaking, the dividing line between“light” and “heavy” nuclei is iron-56. Above this atomic mass, energywill generally be released by nuclear fission reactions; below it, byfusion.

The fusion of two nuclei is generally opposed by the repulsiveelectrostatic force created between the shared electrical charges of thetwo nuclei, specifically the net positive charge of the protonscontained in the nuclei. To overcome this electrostatic force (referredto sometimes as a “Coulomb barrier”), some external source of energy isgenerally required. One way to provide an external source of energy isto heat the reactant atoms. This approach also has the additionalbenefit of stripping the atoms of electrons leaving the atoms as barenuclei. Typically, the nuclei and electrons are formed into plasma.

As the temperature required to provide the nuclei with enough energy toovercome the repulsive electrostatic force varies as a function of thetotal charge, hydrogen, the atom having the smallest nuclear charge,tends to react at the lowest temperatures. Helium also has an extremelylow mass per nucleon and is therefore also energetically favourable as apotential fusion product. Consequently, most fusion reactions are basedon combining isotopes of hydrogen (protium, deuterium, or tritium) toform isotopes of helium, such as ³He or ⁴He.

Reaction cross section, denoted σ, is a measure of the probability of afusion reaction as a function of the relative velocity of the tworeactant nuclei. If the reactant nuclei have a distribution ofvelocities, as would be expected for a thermal distribution withinplasma, then an average over the distributions of the product of crosssection and velocity may be performed. Reaction rate, in terms of fusionper volume per unit of time, may then be defined as

σν

times the product of the number density of reactant atoms. Accordingly,the reaction rate may equal:f=(½n)²

σν

,  (2a)for one reactant, where n represents the number density of atoms of thesingle reactant, and:f=n ₁ n ₂

σν

,  (2b)for two different reactants, where n₁ represents the number density ofatoms of a first reactant and n₂ represents the number density of atomsof a second reactant distinct from the first reactant.

The product

σν

increases from near zero at room temperatures up to significantmagnitudes at temperatures in the range of 10-100 keV (2.2-22 fJ). Forsimilar plasma densities, deuterium-tritium (D-T) fusion tends tobenefit from the lowest ignition temperature. Other possible fusionscycles include the proton-proton (p-p) fusion cycle, which provides theprimary fusion power for stars like the Sun, the deuterium-deuterium(D-D) fusion cycle, the proton-boron (p-¹¹B, the deuterium-helium(D-³He), and the helium-helium (³He-³He) cycle. However, these otherfusion cycles typically require larger ignition energies and, in somecases, depend on ³He (which is relatively scarce on Earth).

Deuterium-Tritium Fuel Cycle

One nuclear reaction presently used in fusion power is thedeuterium-tritium fuel cycle, which may be expressed as:₁ ² D+ ₁ ³ T→ ₂ ⁴He+₀ ¹ n,  (3)where ₁ ²D represented a Deuterium atom, ₁ ³T represents a tritium atom,₂ ⁴He represents a helium atom, and ₀ ¹n represents a free neutron.Deuterium (also referred to as “Hydrogen-2”) is a naturally occurringisotope of hydrogen and, as such, is universally available. Tritium(also referred to as “Hydrogen-3”) is another isotope of hydrogen, butoccurs naturally in small or negligible amounts due to its relativelybrief radioactive half-life of approximately 12.32 years. Consequently,the deuterium-tritium fuel cycle requires synthesis of an ample supplyof tritium atoms to be used in the fusion reaction. Two possiblereactions to synthesize tritium from atoms of lithium include:₀ ¹ n+ ₃ ⁶Li→₁ ³ T+ ₂ ⁴He,  (4)or alternatively:₀ ¹ n+ ₃ ⁷Li→³ ₁ T+ ₂ ⁴He+₀ ¹ n.  (5)

The ⁶Li reaction is exothermic, providing a small energy gain for thereactor in the form of the released heat. On the other hand, the ⁷Lireaction is endothermic, thereby requiring energy, but does not consumethe reactant neutron. At least some ⁷Li reactions may be used to replaceneutrons lost due to reactions with other elements. In either lithiumreaction, the reactant neutron may be supplied by the D-T fusionreaction shown above in equation (3). Most reactor designs takeadvantage of the naturally occurring mix of ⁶Li and ⁷Li lithiumisotopes.

Several limitations are commonly associated with the D-T fuel cycle. Forexample, the D-T fuel cycle tends to produce substantial amounts ofneutrons that induce radioactivity within the reactor structure andimpose significant constraints on material design. Only about 20% of thefusion energy yield appears in the form of charged particles with therest of the fusion energy being provided as neutron, which tends tolimit the extent to which direct energy conversion techniques might beapplied. The use of D-T fusion power also depends on available lithiumresources, which are less abundant than deuterium resources and ingrowing demand due to increased production of Lithium based batteriesand other related technologies. Yet another limitation of the D-T fuelcycle is that it requires handling of the radioisotope tritium. Similarto hydrogen, tritium can be difficult to contain and may leak fromreactors in some quantity.

Proton-Proton Chain Reaction Occurring within Stars

As an alternative to the D-T fuel cycle, the proton-proton chainreaction is a naturally occurring process within stars of approximatelythe same size as the Sun or smaller. The proton-proton chain reaction isone of several fusion reactions by which stars of equal or lesser sizeas the Sun convert hydrogen to helium. However, unlike the D-T-fuelcycle, the proton-proton chain reaction does not induce radioactivitythrough neutron production.

In general, proton-proton fusion will occur when the temperature (i.e.,kinetic energy) of the reactant protons is high enough to overcome theirmutual electrostatic or Coulomb repulsion. While it is now accepted thatproton-proton chain reactions are the dominant thermonuclear reactionsfueling the sun and other stars, originally the temperature of the sunwas thought to be too low to overcome the Coulomb barrier. However,through the discovery and development of quantum mechanics, it is nowpostulated that tunneling of the reactant protons through the repulsiveelectrostatic barrier allows for the proton-proton chain reason to occurat lower temperatures than the classical prediction permitted.

The first of multiple steps in the proton-proton chain reaction involvesthe fusion of two protons into deuterium, in the process releasing apositron, a neutrino and energy, as one of the reactant protons betadecays into a neutron. This step of the proton-proton chain reaction maybe expressed as:₁ ¹H+₁ ¹H→₁ ² D+e ⁺+ν_(e)+0.42 MeV,  (6)where each ₁ ¹H represents a proton, ² ₁D represents a product deuteriumatom, e⁺ represents a positron, and ν_(e) represents a neutrino. Thisfirst step of the proton-proton chain is extremely slow, not justbecause the protons have to quantum tunnel through their Coulombbarrier, but also because the step depends on weak atomic interactions.To illustrate the speed of the reaction, deuterium-producing events arerare enough in the sun that a complete conversion of its hydrogen wouldtake more than 10¹⁰ (ten billion) years given the prevailing conditionsof the sun core. The fact that the sun is still shining is due to theslow nature of this reaction; if the reaction went faster, it istheorized that the Sun would have exhausted its hydrogen long ago.

In the next step of the proton-proton chain reaction, the positron isvery quickly annihilated by an electron and the combined mass energy ofthe positron and electron is converted into two gamma rays and energyaccording to:e ⁺ +e ⁻→2γ+1.02 MeV,  (7)where each γ represents a gammy ray. Subsequently, the deuterium atomproduced in the first step of the proton-proton chain reaction fuseswith another proton to produce a light isotope of helium, namely ³He, afurther gamma ray and energy according to:₁ ² D+ ₁ ¹H→₂ ³He+γ+5.49 MeV  (8)

For temperatures in the range of about 10-14 MK (mega-kelvins), in thefinal step of the proton-proton chain reaction, two of the lightisotopes of helium fuse together to form a ⁴He isotope, two protons andenergy according to:₂ ³He+₂ ³He→₂ ⁴He+₁ ¹H+₁ ¹+12.86 MeV.  (9)

Combining the reaction steps expressed in equations (8) and (9) andcanceling intermediate products, yields the overall proton-protonreaction given by:₁ ² D+ ₁ ² D→ ₂ ⁴He+2γ+23.84 MeV  (10)

In the Sun, the fusion path expressed in Equation (10) occurs with about86% frequency with the remaining 14% due to other fusion reactions thatprevail at temperatures exceeding 14 MK.

Referring initially to FIG. 1, there is illustrated a schematic view ofa thermonuclear reaction system 100 in accordance with at least oneembodiment described herein. Thermonuclear reaction system 100 includesa reaction chamber 110, a fuel injector 120, and a plurality of particlebeam emitters 130 capable of generating a plurality of particle beams135 composed of at least one type of thermonuclear fuel particle. Theparticle beam emitters 130 are supported spatially around and in fluidcommunication with reaction chamber 110, so that during operating of thethermonuclear reaction system 100, the particle beam emitters 130 emitthe plurality of particle beams 135 into the reaction chamber 110. Asdiscussed further below, the plurality of particle beams 135 aredirected into the reaction chamber 110 wherein they interact in such away that a thermonuclear reaction is instigated within the reactionchamber 110, which in at least some cases may be continuous (orpseudo-continuous) and self-sustaining.

The particle beams 135 may be composed wholly or in some cases onlypartially of high energy particles existing in a plasma state. Where theparticle beams 135 are not composed wholly of plasma particles, thenon-plasma particles within the particle beams 135 may retain a netcharge, for example, a positive charge due to electron loss duringionization. In some embodiments, the non-plasma particles within theparticle beams 135 may be neutralized within the reaction chamber 110subsequently to being emitted from the particle beam emitters 130.Alternatively, in some embodiments, the non-plasma particles within theparticle beams 135 may retain their net charge within the reactionchamber 110. Either may be used for the design of thermonuclear reactionsystem 100. However, one disadvantage of utilizing particle beams 135 atleast partially containing charged, non-plasma fuel particles is therepulsive electrostatic forces that exist generally between any twocharged particles. On account of the repulsive electrostatic force, itmay be more difficult to realize a sufficiently high density of fuelparticles within the reaction chamber 110 so as to initiate and sustaina thermonuclear reaction. By neutralizing any charged, non-plasma fuelparticles within the reaction chamber 110 and thereby eliminatingrepulsive electrostatic forces between fuel particles in the particlebeams 135, particle densities required for thermonuclear fusion maygenerally be easier to attain within the reaction chamber 110.

In some embodiments, the particle beams 135 may be generated by ionizinga supply of the at least one type of thermonuclear fuel particleprovided by the fuel injector 120. After ionization, the chargedparticles within the particle beam emitters 130 may then be acceleratedtoward the reaction chamber 110. To neutralize any charged, non-plasmaparticles in the particle beams 135, for example, a supply of alow-pressure reactive gas may be pumped or otherwise provided into thereaction chamber 110 through a suitable gas inlet, so that individualcharged particles in the particle beams 135 react with the neutralizinggas within the reaction chamber 110 and lose any retained charge.

As shown in FIG. 1, each of the particle beams 135 is directed toward acommon focal region 140 of reaction chamber 110. The particle beams 135may be directed toward the common focal region 140 by arranging theparticle beam emitters 130 around the reaction chamber 110 in anysuitable three-dimensional spatial orientation. For example, theparticle beam emitters 130 may be arranged in a substantially sphericalarrangement around the reaction chamber 110 or otherwise so that theparticle beam emitters 130 are essentially equidistant from the commonfocal region 140. Alternatively, the particle beam emitters 130 may bearranged to be substantially symmetric in at least three differentplanes (e.g., as defined in a Cartesian coordinate system), which may insome cases be mutually orthogonal. However, other three-dimensionalspatial orientations for the particle beam emitters 130 are possible aswell.

In some embodiments, converging elements 150 may be provided in the pathof the particle beams 135 to assist in directing the particle beams 135towards the common focal region 140. While only one example of theconverging elements 150 is explicitly illustrated in FIG. 1, in someembodiments, additional converging elements may be included inthermonuclear reaction system 100. Each of the converging elements 150included may be associated with a single one of the particle beams 135or, alternatively, two or more of the particle beams 135.

In some embodiments, where the particle beams 135 contain at least somecharged, non-plasma fuel particles, some of the convergent elements 150may be implemented using a magnetic lens. For example, the magnetic lensmay consist of several electromagnetic coils arranged into a quadrupole,a sextupole, or some other suitable arrangement. When theelectromagnetic coils are energized, the resulting quadrupolar orsextupolar magnetic field has a generally convex shape that deflectscharged particles travelling through the magnetic field. The amount ofdeflection is controllable based upon the strength of the magneticfield, which in turn may be controlled by varying the energizing currentsupplied to the electromagnetic coils. In this way, the magnetic lensmay be effectively utilized to focus or otherwise converge the particlebeams 135 at the common focal region 140.

Alternatively, some of the converging elements 150 may be implementedusing an electrostatic lens configured as a focusing element of chargedparticle beams. For example, in some embodiments, the electrostatic lensmay be an Einzel lens, a cylinder lens, an aperture lens or a quadrupolelens. In some embodiments, the converging elements 150 may be a mixtureof magnetic and electrostatic lenses.

Where the particle beams 135 are composed completely or nearlycompletely of plasma fuel particles, electrostatic or magnetic lenseswill not generally be suitable for implementing the converging elements150 because the plasma particles are electrically neutral overall andtherefore not generally responsive to electromagnetic fields. However,it is still possible to alter the path of a neutral particle beamexisting in complete or near complete plasma state and thereby focus theparticle beams 135 at the common focal region 140. One exampleconfiguration to achieving this result is described below in more detailwith reference to FIG. 2.

The inside surface of the reaction chamber 110 may be coated with asuitable insulating material to absorb any high energy gamma-raysproduced during the thermonuclear reactions taking place within thereaction chamber 110. Different materials having generally differentthermal and electrical properties may be used to coat the inside surfaceof the reaction chamber 110. For example, melting point and heatabsorption capability may be two of the relevant considerations forchoosing an appropriate coating material. As a coolant liquid (notshown) may be applied also to the inside surface of the reaction chamber110 in some embodiments, another relevant consideration for the coatingmaterial may be its chemical reactivity with the particular coolantfluid used. A coating material that is generally non-reactive with thecoolant liquid may be preferable. In some embodiments, nuclear graphiteor graphene, tungsten or other materials having melting points equal toor greater than those of graphite and tungsten may be used for thematerial used to coat the inside surface of the reaction chamber 110.

Converging the particle beams 135 at the common focal region 140 causesthe particle density existing at the common focal region 140 toincrease. If the particle density rises to sufficiently high levels, aplasma sphere 145 is created in the vicinity of the common focal region140 and having a sufficiently high temperature so as to instigate athermonuclear fusion reaction within the reaction chamber 110. Forexample, the density of the plasma sphere 145 may be comparable to thedensities found in the center of the Sun (i.e., up to 160,000 kg/m³). Byconverging a sufficiently large number of the particle beams 135, eachof which is composed of thermonuclear fuel particles accelerated withsufficient kinetic energy, the required particle densities for sustainedthermonuclear reactions may be achieved in the reaction chamber 110.This result is also achieved without the contribution of gravity effectspresent in stars that assisting in sustaining the thermonuclearreactions that naturally occur in those and similar environments.Rather, particle and energy concentration is realized in the reactionchamber 110 through the acceleration and convergence of particle beams135 at common focal region 140.

Optionally, an additional supply of input energy into the reactionchamber 110 may be directed toward to the common focal region 140 inorder to assisting in igniting the plasma sphere 145 and therebyinstigate the thermonuclear reaction. Accordingly, in some embodiments,a plurality of lasers 160 may be arranged spatially around reactionchamber 110 and, like the particle beam emitters 130, oriented towardcommon focal region 140 near the center of the reaction chamber 110. The160 may generate and emit a plurality of laser beams 165 that also areconvergent at common focal region 140. In some embodiments, laser guidetubes made of, for example, glass fibers (not shown) may extend somedepth into reaction chamber 110 in order to guide the laser beams towardthe common focal region 140.

In alternative embodiments, supplemental energy input devices (notshown) other than, or in addition to, the lasers 160 may also be usedfor igniting the plasma sphere 145 to assist instigation ofthermonuclear reactions. For convenience only, and without limitation,only a single one of the lasers 160 is shown explicitly in FIG. 1,although more than one laser or other supplemental energy input devicemay be used. Moreover, any number of lasers 160 may be included and maybe arranged spatially around the reaction chamber 110 in any suitablearrangement in order to accommodate the desired number of lasers 160.

In some embodiments, the energy generated by the thermonuclear fusionreactions occurring at or near common focal region 140 is sufficient tomaintain the plasma sphere 145 at a sufficiently high temperature thatcontinuous and sustained thermonuclear reactions may be instigatedwithout the use of supplemental energy input devices (e.g., lasers 160).Accordingly, in some embodiments, the lasers 160 or other supplementalenergy input devices may be omitted from the thermonuclear reactionsystem 100 and convergence of a sufficient number of the particle beams135 accelerated to sufficient kinetic energies may suffice by themselvesto both ignite and sustain thermonuclear fusion reactions.

However, convergence of the particle beams 135 by itself may not besufficient to ignite the plasma sphere 145 and instigate a thermonuclearfusion reaction. Accordingly, in some embodiments, the lasers 160 orother supplemental energy input devices may be operated initially untila thermonuclear fusion reaction has been instigated within the reactionchamber 110, but thereafter then disabled. In that case, the heatgenerated from particle collisions due to convergence of the particlebeams 135 may be sufficient to sustain continuous thermonuclearreactions within the reaction chamber 110 without benefiting fromadditional input energy supplied by the lasers 160 or other supplementalenergy input devices.

Determining the specific parameters of thermonuclear reaction system 100will generally involve detailed analytical calculations, computersimulations and fine-tuning fusion firing experiments. For example,specific parameters that should be determined include the number,density, temperature, size and velocity of particle beams 135, as wellas the separation distance between particle beam emitters 130 and commonfocal region 140, and also the thickness of the coating material ofreaction chamber 110. Additionally, if the lasers 160 are included inthe thermonuclear reaction system 100, then the number, frequency andsize of lasers 160 and laser beams 165 (and/or other supplemental energyinput devices) should be determined, along with the distance between anylaser guide tubes (where provided) and the common focal region 140.Different combinations and configurations of the elements describedherein may be possible in different embodiments of the thermonuclearreaction system 100.

Reference is now made to FIG. 2, which illustrates a schematic view ofan exemplary particle beam emitter 200, which may be used to implementany or all of the particle beam emitters 130 shown in FIG. 1 inaccordance with at least one embodiment. Particle beam emitter 200includes a hollow cylindrical particle beam tube 210 having a first endportion 212, a second end portion 214 and an inner surface (not shown).Particle beam tube 210 may be composed of an electrically conductivematerial having a melting temperature substantially above an equilibriumtemperature of the high energy plasma or ionized particles housed withinthe particle beam emitter 200. In certain embodiments, particle beamtube 210 may be formed of a material or composition having a meltingtemperature exceeding 1,800° C. Alternatively, the inner surface of theparticle beam tube 210 may be coated with a material or compositionhaving a melting temperature of 1,800° C. or higher. Examples ofsuitable materials for forming or coating the inner surface of theparticle beam tube 210 include, but are not limited, to tungsten andgraphite. In some embodiments, particle beam tube 210 may be composed ofa hollow graphene cylinder coated on the inner surface with a layer oftantalum hafnium carbide (Ta₄HfC₅), which has a melting point of about4200° C., or some other chemical compound having a generally highermelting point than carbon based materials such as graphene.

In the example arrangement illustrated in FIG. 2, first end portion 212of particle beam tube 210 is in fluid communication with a fuel injector(such as fuel injector 120 shown in FIG. 1) to receive a plasma 220containing at least one type of thermonuclear fuel particle. Forexample, the plasma 220 may contain particles of ₁ ¹H or ₁ ²D or someother type of thermonuclear fuel particle. Plasma 220 may typically beprovided by the fuel injector to the particle beam tube 210 at arelatively high pressure and temperature. In order to provide the supplyof the plasma 220 to the particle beam emitter 200, the fuel injectormay convert an internal or separate external supply of thermonuclearfuel particles into their plasma state by heating and/or ionizingprocesses prior to the plasma 220 being received into the first endportion 212 of the particle beam tube 210.

Second end portion 214 of particle beam tube 210 is located opposite tothe first end portion 212 and may be in fluid communication with thereaction chamber 110 (FIG. 1). This allows particle beam emitter 200 toemit a corresponding one of the particle beams 135 (FIG. 1) intoreaction chamber 110. In some embodiments, at least a portion of secondend portion 214 partially extends into reaction chamber 110 to a desireddepth. The extension depth of the second end portion 214 may be varieddepending on the application and to meet design and/or performancecriteria for the thermonuclear reaction system 100 (FIG. 1). However, aminimum distance between second end portion 214 of each particle beamtube 210 and common focal region 140 (FIG. 1) should be maintained toensure safe operation of the particle beam emitter 200 under the extremeoperating conditions prevailing within reaction chamber 110. Asdiscussed above, design calculations, computer simulations andfine-tuning fusion firing tests are required to determine the designparameters of embodiments of thermonuclear reaction system 100.

Particle beam emitter 200 may also include an electromagnetic system 230for generating an electromagnetic field (not shown) to provide radialconfinement and linear acceleration of plasma 220 within particle beamtube 210 using a variation of the “pinch” concept (sometimes alsoreferred to as the “Z-pinch” concept). According to the pinch concept,the interaction between an electrical current flowing through plasma andan induced (and/or externally applied) magnetic field causes inwardcompression of the plasma in a direction orthogonal to the direction ofthe current flow through the plasma. In effect, by inducing an axialcurrent flowing in a direction parallel to a central axis 216 ofparticle beam tube 210, plasma 220 behaves somewhat like a plurality ofcurrent-carrying wires where each wire is carrying current in the sameaxial direction. Consequently, the plasma “wires” are each pulled towardeach other by the mutually acting Lorentz forces, the overall result ofwhich being that plasma 220 contracts itself inwardly toward the centralaxis 216 of particle beam tube 210 wherein the plasma 220 isconcentrated. As plasma 220 contracts inwardly and concentrates, thedensity of plasma 220 increases; denser plasmas can generate densermagnetic fields, increasing the inward force acting on plasma 220, andfurther compressing and concentrating the plasma 220 in the vicinity ofthe central axis 216.

In order to achieve pinching of the plasma 220, the electromagneticsystem 230 may include a voltage supply 232 electrically coupled toparticle beam tube 210 and configured to generate a primary electricalcurrent 234 flowing in the hollow cylindrical section of particle beamtube 210. For example, the voltage supply 232 may create a potentialdifference between first end portion 212 and second end portion 214 sothat the primary electrical current 234 flows therebetwen around theentire or substantially the entire periphery of the hollow cylindricalsection. The magnetic field associated with the primary electricalcurrent 234 induces a secondary electrical current 236 flowing generallyaxially within plasma 220 that creates the z-pinch effect detailedabove.

When the parameters of primary electrical current 234 are suitablycontrolled (e.g., frequency and amplitude), secondary electrical current236 will interact with the magnetic field associated with the primaryelectrical current 234 to generate a radial force field 238 withinparticle beam tube 210. Radial force field 238 is directed generallyinwardly towards central axis 216. Radial force field 238 will urge anyplasma 220 present in particle beam tube 210 toward central axis 216. Asthe density of plasma 220 increases, the resulting pressure gradientaccelerates plasma linearly along central axis 216. A pressure valve orthe like (not shown) at first end portion 212 prevents the plasma 220from flowing back towards the fuel injector, and forces plasma 220toward second end portion 214 at a relatively high velocity, where it isejected from particle beam emitter 200 into the reaction chamber 110 asone of the particle beams 135. The exit velocity of the particle beams135 may be controlled according to the pressure gradient experienced byplasma 220 during the electromagnetic pinch: the higher the pressuregradient experienced by the plasma 220, the higher the exit velocity ofthe particle beams 135.

In some embodiments, the voltage supply 232 may be coupled to theparticle beam tube 210 included in each of an opposing pair of theparticle beam emitters 130. As used herein, two of the particle beamemitters 130 may be understand to oppose one another when orientedapproximately 180-degrees apart in a common plane so that the pair ofparticle beam emitters 130 are substantially in opposition to oneanother along a linear trajectory. Accordingly, when the particle beams135 are emitted from the particle beam emitters 130 and the plasmasphere 145 is ignited, a closed electrical loop is formed between eachopposing pair of the particle beam emitters 130 and the voltage supply232 via the particle beams 135 and the plasma sphere 145. The voltagesupply 232 (or alternatively another suitable voltage supply) may alsobe coupled to multiple opposing pairs of the particle beam emitters toform multiple corresponding closed electrical loops.

A high voltage initially supplied by the voltage supply 232 may be usedto electrify individual fuel particles contained in the opposing pair ofthe particle beam emitters 130 forming part of the closed electricalloop. In response to application of the high voltage, the fuel particlesmay be turned into plasma 220 and thereafter develop the secondaryelectrical current 236 that causes pinching of the plasma 220 toward thecentral axis 216. Due to the closed electrical looping, the pinching mayoccur both within the particle beam tube 210, but may also continue asthe particle beams 135 travel toward and converge at the common focalregion 140, thereby further raising the particle density realized withinthe plasma sphere 145. The initially applied high voltage may bemaintained or thereafter reduced in order to supply a desired level ofconstant electrical current in order to achieve desired level of energyconcentration around the central axis 216 in the colliding pair of theparticle beams 135. The number of pairs of the particle beams 135included in closed electrical loops may also vary in order to create adesired level of energy concentration at common focal region 140 due tofocusing of the particle beams 135.

In some embodiments, electromagnetic system 230 also includes aplurality of electromagnetic coils 240 aligned axially about centralaxis 216 along at least a portion of particle beam tube 210.Electromagnetic coils 240 are used to generate an axial magnetic field(not shown) within particle beam tube 210 that provides supplementalradial confinement of plasma 220 within particle beam tube 210.Consequently, the stability of the plasma 220 is increased as the plasma220 is compressed along central axis 216 (as will be discussed furtherbelow). Electromagnetic coils 240 may typically surround particle beamtube 210 and may generally be located in close proximity to particlebeam tube 210. In certain embodiments, the exterior of particle beamtube 210 supports the electromagnetic coils 240, althoughelectromagnetic coils 240 may be separated from particle beam tube 210by suitable thermal and/or electrical insulation members (not shown).Inclusion of electromagnetic coils 240 within the particle beam emitter200 is optional and, in some cases, may depend on the required velocityof particle beams 135 for a particular fusion reactor design.

Alternatively, or additionally, particle beam emitter 200 may includeexternal magnets 250 to provide supplemental radial confinement ofplasma 220 within particle beam tube 210. External magnets 250 mayinclude permanent magnets or electromagnets, and may be arranged in anysuitable configuration that provides the desired magnetic field anddesired supplemental confinement. For example, the position of theexternal magnets 250 relative to the particle beam tube 210 may be fixedor the external magnets 250 may be movably secured in relation to theparticle beam tube 210 so as to be movable about the particle beam tube210. The magnetic field generated by the external magnets 250 maytherefore be static or time-varying as the case may be.

In some embodiments, the particle beam emitter 200 may include one pairof permanent magnets or electromagnets that are rotatable about thecentral axis 216. The time-varying magnetic field resulting fromrotation of the external magnets 250 about the central axis 216 is alsoused to induce the secondary electrical current 236 within plasma 220flowing in a generally axial direction (i.e., parallel to the centralaxis 216). To be rotatable about the central axis 216, the externalmagnets 250 may be attached to or otherwise supported by the particlebeam tube 210. Alternatively, the external magnets 250 may be supportedby an external support system (not shown) proximate to the particle beamtube 210.

In some embodiments, the external magnets 250 may include more than onepair of permanent magnets or electromagnets. Each pair of permanentmagnets or electromagnets may be supported within the particle beamemitter 200 using a similar arrangement to what is described above. Theconfigurations of each pair of permanent magnets or electromagnets maybe identical or may vary with respect to one another. For example, theradial distance to the central axis 216 may be the same or differentfrom pair to pair. Accordingly, at least one pair of permanent magnetsor electromagnets may be spaced apart from the central axis 216 by adifferent radial distance from at least one other pair. Alternatively,each pair of permanent magnets or electromagnets may have the sameradial spacing relative to the central axis 216.

The axial length and positioning of the external magnets 250 may also bevaried in different embodiments. For example, in some embodiments, theexternal magnets 250 may span the entire axial length or nearly theentire axial length of the particle beam tube 210 (this arrangement isshown in FIG. 2 for illustrative purposes only). Alternatively, in someembodiments, two or more of the external magnets 250 separated by airgaps may be arranged in axial alignment along the length of the particlebeam tube 210. In this case, the width of the air gaps between theexternal magnets 250 in axial alignment may be approximately equal. Forexample, two or three or any other suitable number of the externalmagnets 250 may span the axial length of the particle beam tube 210.

In some embodiments, particle beam emitter 200 is operated with athermonuclear fuel mixture comprised of hydrogen and deuterium gases.The hydrogen and deuterium gases are heated in a fuel injector (such asfuel injector 120) in order to dissociate electrons from the hydrogenand deuterium nuclei until the hydrogen and deuterium gases existcompletely or almost completely in their plasma states, thereby formingthe plasma 220. Typically, this will involve heating the thermonuclearfuel mixture within the fuel injector to a temperature of at 1,800° C.or higher. Once heated, the mixture of hydrogen and deuterium plasma issupplied to first end portion 212 of particle beam tube 210 from thefuel injector. Inside the particle beam tube 210, the primary electricalcurrent 234 generated by electromagnetic system 230 induces thesecondary electrical current 236 within the plasma 220. As discussedabove, the resulting electromagnetic field provides radial confinementand axial acceleration of the plasma 220 toward the second end portion214.

In order to heat up the hydrogen and deuterium gases, the fuel injectorin some embodiments may include a plurality of fuel channels fed throughat least one high temperature furnace. The hydrogen and deuterium gasesare pumped through the fuel channels (each fuel channel may house onlyone of the two gases) wherein heat radiated from the high temperaturefurnace brings the hydrogen and deuterium gases to the desiredtemperatures. To withstand the heat generated by the high temperaturefurnace, each of the fuel channels may be composed of a material ormaterial composition having a very high melting point, for example, wellabove 1,800° C. For example, as noted above, graphite and tungsten aresome non-limiting examples of suitable materials for the fuel channels.

Alternatively, in some embodiments, the hydrogen and deuterium gases maybe mixed together within the fuel injector and converted into theirplasma states through heating by other mechanisms or processes. Forexample, the mixture of hydrogen and deuterium gases may be subject tohigh-frequency electromagnetic waves during transport through the fuelinjector to the particle beam emitter 200. The energy imparted by thehigh-frequency electromagnetic waves may be used to increase the kineticenergy of the pumped hydrogen and deuterium to high enough levels.Heating by high-frequency electromagnetic waves is similar to what takesplace in some current tokamak machines, such as ITER. The fuel injectoragain may be formed or coated from a material or material compositionhaving a very high melting point, for example, well above 1,800° C.Graphite, tungsten and tantalum hafnium carbide (Ta4HfC5) provide somenon-limiting examples of suitable materials for the fuel injector.

The schematic arrangement shown in FIG. 2 is merely illustrative, andother arrangements could be used to effect particle beam emission. Forexample, each particle beam emitter 200 may comprise a plurality ofparticle beam tubes (similar to the particle beam tube 210), and each ofthe particle beam tubes may be capable of emitting one of the particlebeams 135 into reaction chamber 110. That is, in some embodiments, theparticle beam emitter 200 may be capable of emitting a plurality ofparticle beams 135 into reaction chamber 110.

Referring now to FIGS. 1 and 2, in some embodiments, one or moreparticle beam tubes (such as the particle beam tube 210) can extend intoreaction chamber 110 by a certain distance to provide (additional)directional guidance to particle beams 135 in order to increase theconvergence at common focal region 140 with other individual particlesbeams in the particle beams 135. However, a minimum distance between thesecond end portion 214 of each particle beam tube 210 and common focalregion 140 should be maintained to ensure safe operation of particlebeam emitters 130 under the extreme operating conditions in reactionchamber 110.

The second end portion 214 of the particle beam tube 210 may also bemodified to have a gentle and smooth bend into a desired direction. Thecurvature of the second end portion 214 may be controlled to slightlyalter or deviate the direction of the primary electrical current 234near the second end portion 214. Consequently, the secondary electricalcurrent 236 induced by the magnetic field associated with the primaryelectrical current 234 would also bend or deviate into the same desireddirection due to the coupling between the primary electrical current 234and the secondary electrical current 236. The deviation of the secondaryelectrical current 236 then alters the electromagnetic field within theparticle beam tube 210 in a way that the high-energy particles emittedfrom the particle beam tube 210 are focused at and converge upon thecommon focal region 140. As noted above, this alternative confirmationof the particle beam emitter 200 may be used as an alternative or inaddition to the converging elements 150.

As discussed above, determining the specific parameters of thermonuclearreaction system 100 will involve detailed analytical calculations,computer simulations and fine-tuning fusion firing experiments. Forexample, specific parameters that should be determined include thethickness and diameter of particle beam tube 210, the respectivemagnitudes of primary electrical current 234 and secondary electricalcurrent 236, the magnitude and configuration of the magnetic fieldsgenerated by electromagnetic coils 240 and/or external magnets 250, andthe separation distance between the particle beam tube 210 and thecommon focal region 140.

The thermonuclear reaction system 100 may operate using one or moretypes of suitable thermonuclear fuel particles as part of one or moreknown fusion reaction paths. For example, thermonuclear reaction system100 can use deuterium, tritium, and lithium to effect adeuterium-tritium reaction cycle, as discussed above. In someembodiments, thermonuclear reaction system 100 uses a combination of ₁¹H and ₁ ²D in order to effect a proton-proton fusion cycle, alsodiscussed above. While ₁ ²D is the primary source of energy in aproton-proton fusion cycle, ₁ ¹H particles are employed to produce asufficient quantity of the intermediate product ₂ ³He with theparticipation of ₁ ²D, although as discussed above ₁ ¹H can also beconverted to ₁ ²D in a slow process due to the effects of quantumtunneling and weak interactions.

The supply of ₁ ¹H and ₁ ²D thermonuclear fuel particles for such aproton-proton reaction is virtually inexhaustible, as approximately onein every 6,500 hydrogen atoms on Earth is a deuterium atom, and both ₁¹H and ₁ ²D can be readily extracted from seawater. One gallon ofseawater would, in some embodiments, provide the equivalent energyoutput of approximately 300 gallons of gasoline.

Referring now to FIG. 3, a schematic view of a thermonuclear reactionsystem integrated with an existing nuclear fission reactor design (suchas the CANDU design) is illustrated in accordance with at least oneembodiment. In this example embodiment, a continuous proton-protonfusion reaction is generated in a thermonuclear reaction system (such asthe thermonuclear reaction system 100 shown in FIG. 1), and hydrogen anddeuterium thermonuclear fuel particles are extracted from seawater in aseparation facility 310.

After the removal of impurities, seawater containing deuterated water(sometimes referred to as HDO) and H₂O enters a separation facility 310,where ₁ ¹H and ₁ ²D are separated from O₂. The ₁ ¹H and ₁ ²D gasesproduced by separation facility 310 subsequently enter a fuel injector320 (which may be similar or equivalent to fuel injector 120 asdescribed herein above with reference to FIG. 1) where the ₁ ¹H and ₁ ²Dgases are heated to form a plasma of thermonuclear fuel particles to beprovided to one or more particle beam emitters 330 (which may be similaror equivalent to particle beam emitter 200 as described herein abovewith reference to FIG. 2).

As described above, particle beam emitters 330 may emit particle beamsconsisting of thermonuclear fuel particles towards a common focal region335 of a reaction chamber 340, creating density and temperatureconditions sufficient to instigate and, in at least some cases, sustaina continuous (or pseudo continuums) thermonuclear fusion reaction.

A primary cooling system 350 uses water (or any other suitable coolantliquid) to absorb at least some of the heat generated by thethermonuclear fusion reaction taking place within reaction chamber 340.Primary cooling system 350 is also connected to one or more steamgenerators 360; steam output from steam generator 360 can be used todrive turbines and generators (not shown) to produce electricity.

Integration with an existing nuclear reactor design may minimize theduration for design and manufacturing of an overall fusion reactor. Forexample, the existing CANDU reactor may be modified in accordance withembodiments of the present thermonuclear reaction system by substitutingthe Calandria fission reactor core with a fusion reaction chamber,removing the fuel bundles and fuelling machines, replacing the fuelchannel assemblies with simple pressure tubes, installing particle beamemitters surrounding the fusion chamber, replacing the heavy water usedin the CANDU design with regular water (as no neutrons need to bemoderated), replacing the heavy water pressure reservoir with a gascollection tank 370, and adding the separation facility 310.

Gas collection tank 370 is used to collect un-reacted thermonuclear fuelparticles and fusion reaction products, as not all of the ₁ ¹H and ₁ ²Dparticles injected into the reaction chamber may undergo a fusionreaction with another reactant particle. In some embodiments, the gascollection tank 370 may operate based on the relative buoyancies ofdifferent fuel particles. For example, there is a relatively largedifference in density between the reactant fuel particles in athermonuclear reaction (e.g., the ₁ ¹H and ₁ ²D particles) and theproduct particles of the fusion reaction (e.g., He particles), on theone hand, and the coolant fluid, on the other hand. Accordingly, thelighter gas particles will generally flow up through the coolant fluiddue to buoyancy effects, resulting in a concentration of the lighter gasparticles at an upper portion of the gas collection tank 370. Therelatively heavy coolant fluid will correspondingly concentrate towardthe lower portion of the gas collection tank 370.

In order to separate the lighter gas particles from the heavier liquidcoolant, the gas collection tank 370 may include an outlet valve orother external feed in the upper portion through which the gas may becontinually pumped. As the lighter gases exist as a mixture with thecoolant fluid flowing through the primary cooling system, some of thegases may remain un-collected after one cycle of the coolant fluidthrough the primary cooling system. However, un-collected gases mayeventually be collected by the gas collection tank 370 as the coolantliquid is continually pumped through the primary cooling system duringadditional cycles.

The un-reacted gases and fusion product collected in gas collection tank370 may then be delivered to separation facility 310 for reuse. Inaddition to the un-reacted gasses and the fusion product, a small amountof coolant water close to the central region may dissociate into H₂, D₂and O₂ due to the heat generated by a thermonuclear fusion reactiontaking place within reaction chamber 340. If coolant water dissociatesinto H₂, D₂ and O₂, the H₂, D₂ and O₂ will be collected in gascollection tank 370 and moved to separation facility 310, following thesimilar path as H₂, D₂ and He gases shown in FIG. 3.

In some embodiments, the gas collection tank 370 may be modified byinstallation of at least one pressure valve in order to achieve an addedfunctionality, i.e., coolant water pressure reservoir. This modificationto the gas collection tank 370 would permit the gas collection tank 370to control and achieve a desired level of pressure for the coolantliquid being pumped through the primary cooling system.

In order to maintain a desired level of ₁ ²D concentration in the fuelparticle circulation, for optimal performance of the thermonuclearreaction system, certain amount of ₁ ¹H gas may be moved out ofseparation facility 310, along with the O₂ and He gases. The desiredlevel of ₁ ²D concentration may be determined by detailed designcalculations; the higher the ₁ ²D concentration, the larger the fusionenergy output of the thermonuclear reaction system.

In some embodiments, un-reacted fuel particles collected from the gascollection tank 370 may be mixed together with newly supplied fuelparticles of the same or a different type in a closed loop circulation.For example, particles of Hydrogen-1 or a mixture of Hydrogen-1 andHydrogen-2 collected from the gas collection tank 370 may be mixedtogether with a new supply of Hydrogen-1 or a mixture of Hydrogen-1 andHydrogen-2. However, this example is not limiting. The resulting closedloop circulation of collected and new fuel particles may include one ormore separation facilities (e.g., separation facility 310 in FIG. 3),one or more fuel injectors (e.g., fuel injector 120 in FIG. 1) and aplurality of particle beam emitters (e.g., particle beam emitter 200 inFIG. 2). The minimum operating temperature in the closed loopcirculation may be maintained at 1800° C. or greater by the heatgenerated from thermonuclear fusion reactions occurring within thereaction chamber 110 as described herein. As a result, the fuelparticles used to drive the thermonuclear fusion reactions aremaintained essentially continuously in a plasma state without having there-heat the fuel particles into plasma in the fuel injector prior tosupplying the fuel particles to the particle beam emitter forre-emission in the reaction chamber 110.

As discussed above, thermonuclear reaction system 100 preferably uses acombination of ₁ ¹H and ₁ ²D in order to effect a proton-proton fusioncycle. However, future generations of nuclear fusion reactors, may alsobe able to employ other elements—such as isotopes of He, B, Li, C, Ne,O, etc.—as thermonuclear fuel. In theory, a series of fusion reactionscan be designed in order to maximize the energy output from a fusionreaction path (For example, a fusion reaction could be designed with thefusion path H→He→C→Ne→O→Si).

In some embodiments, seawater may be purified to remove sand, salt orother impurities and provided, through at least one fuel injector, tosome or all of the particle beam emitters 200 shown in reference to FIG.2 as a source of thermonuclear fuel. The purified seawater may be heatedup in the at least one fuel injector or subsequently in the particlebeam emitters. Heating of the purified seawater causes the watermolecules to dissociate into O₂, H₂ and D₂ gases and, with asufficiently hot source of heat, at least some part of the H₂ and D₂gases further turn into plasma due to increasing temperature.Accordingly, in some embodiments, the purified seawater is automaticallyseparated into different thermonuclear fuel types by heating inside theat least one fuel injector or subsequently inside at least some of theparticle beam emitters 200. Consequently no additional separationfacilities will be needed in at least some cases to provide thethermonuclear fuel used in the thermonuclear reaction system 100.

While the above description provides examples of the embodiments, itwill be appreciated that some features and/or functions of the describedembodiments are susceptible to modification without departing from thespirit and principles of operation of the described embodiments.Accordingly, what has been described above has been intended to beillustrative only and non-limiting.

The invention claimed is:
 1. A particle beam emitter comprising: ahollow particle beam tube having a first end portion, a second endportion, and a longitudinal axis; and an electromagnetic systemcomprising a voltage supply electrically coupled to the hollow particlebeam tube and configured to generate a primary electrical currentflowing axially in the hollow particle beam tube from the first endportion towards the second end portion, whereby a primary magnetic fieldassociated with the primary electrical current is operable to induce asecondary electrical current in a plasma located within the hollowparticle beam tube, the secondary electrical current flowing generallyaxially within the plasma and causing the plasma to contract inwardlytowards the longitudinal axis.
 2. The particle beam emitter of claim 1,further comprising a plurality of electromagnetic coils aligned axiallywith and surrounding at least a portion of the hollow particle beam tubefor generating an axial magnetic field within the hollow particle beamtube.
 3. The particle beam emitter of claim 2, further comprising aninsulation member positioned between the plurality of electromagneticcoils and the hollow particle beam tube.
 4. The particle beam emitter ofclaim 1, further comprising a pair of electromagnets positioned exteriorto the hollow particle beam tube and rotatable about the longitudinalaxis.
 5. The particle beam emitter of claim 1, wherein the voltagesupply is configured to generate the primary electrical current bycreating a potential difference between the first end portion and thesecond end portion.
 6. The particle beam emitter of claim 1, wherein thefirst end portion is configured to receive plasma from a fuel injector.7. The particle beam emitter of claim 6, further comprising a pressurevalve positioned between the fuel injector and the first end portion ofthe hollow particle beam tube.
 8. The particle beam emitter of claim 1,wherein the hollow particle beam tube is made from at least one oftungsten and graphite.
 9. The particle beam emitter of claim 1, whereinthe hollow particle beam tube comprises a hollow graphene cylinderhaving an inner surface coated with tantalum hafnium carbide.